A popular exchange-traded fund used to track Brazil's equity market fell sharply on Thursday, coinciding with a sharp decline in the Brazil's main stock exchange. The iShares MSCI Brazil ETF was recently down 8%, putting it on track for its worst daily fall since May 18, 2017, according to FactSet data, while the BOVESPA Index was off 5.7%. The decline for Brazilian equities comes amid apprehension over recent labor unrest, with a strike of truckers, shaky economic growth and a presidential election slated for October. Reports on Thursday suggested that Brazil's central bank attempted to intervene to stem a selloff of the country's currency against the dollar which was down about 2% against on the day and 4% thus far this week. The Brazilian ETF, meanwhile, has lost more than 10% of its value so far this week and is on pace to shed 20% in 2018. By comparison, the S&P 500 index was up 3.5% so far this year, while the Dow Jones Industrial Average has returned about 2% in the first six months of the year.